The present invention relates to an improved gripper for supporting an object. More specifically, the present invention relates a gripper for supporting a thin disk such as a glass substrate, a flat panel display, a patterned or unpatterned semiconductor substrate, and the like particularly during a cleaning process.
Semiconductor substrates are often cleaned within a tank of fluid (or a bath) followed by a rinsing process (e.g., by submersing the substrate in rinsing fluid, or by spraying the substrate with rinsing fluid). A drying apparatus such as a spin-rinse-dryer (SRD) is typically used to rinse and to dry a substrate.
Spin-rinse-dryers typically include a flywheel adapted to spin a substrate and a plurality of grippers attached to the flywheel and adapted to support a substrate thereon. The flywheel spins the substrate while the substrate is sprayed with rinsing fluid, and, after the fluid spray ceases, spin dries the substrate. The grippers which hold the substrate in place on the flywheel, may move between an open and closed position. In the open position, a substrate handler may place a substrate on the grippers and also may extract a rinsed and dried substrate therefrom. In the closed position, the grippers may clamp a substrate in place on the flywheel. As the grippers move between the open and closed position, precise repeatable positioning of the grippers is essential in order to avoid damaging a substrate by grasping it too tightly or allowing a substrate to become unseated from the flywheel by grasping the substrate too loosely. The mechanical parts used to open and close many conventional grippers are subject to wear, which may result in unrepeatable gripping as well as creating particles which may contaminate the substrate.
Accordingly, a need exists for an improved gripper.
The invention provides a gripper assembly comprising a mounting base having a first magnet coupled thereto and having a moveable gripper coupled to the mounting base. The moveable gripper has a second magnet coupled thereto and comprises an end effector adapted to contact a wafer. The first and second magnets are adapted so that the magnetic force therebetween biases the end effector away from the mounting base. An inventive method of gripping a substrate comprises coupling a moveable gripper to a mounting base and magnetically biasing the moveable gripper in a closed position.
Other features and aspects of the present invention will become more fully apparent from the following detailed description of the preferred embodiments, the appended claims and the accompanying drawings.